1. Field of the Invention
The present invention relates to a valve nozzle used for a synthetic resin molding machine, more specifically, a valve nozzle and a shut-off nozzle used for runner-less molding.
2. Description of the Prior Arts
To obtain moldings with stable quality by a resin molding machine, temperature management control is an essential matter during melting of a raw material resin, injecting of the melting resin into a mold and solidifying inside the mold, and removal from the mold after solidifying.
To control the temperature of the resin injected into the mold, there is known a technique of controlling the temperature of the cavity by supplying a coolant into the mold, proposed in Patent Documents of Document 1 (Japanese Patent No. 3345196), Document 2 (Japanese Examined Patent Publication No. H07-59375), Document 3 (Japanese Unexamined Patent Publication No. H04-65214), Document 4 (Japanese Unexamined Utility Model Publication No. H04-11614), and so on.
According to the inventors' research, with the techniques shown in the above Documents 1 through 4, satisfactory temperature control is possible during injection molding by using a general resin, and moldings with stable quality are obtained, however, in the case of injection molding of silicone rubber or urethane rubber, etc., that requires more strict temperature control, in particular, foaming injection molding, it was found that properties changed when injecting.